摘要目的 探讨(牙合)干扰去除时间与大鼠咀嚼肌机械痛觉过敏恢复的关系,为临床咬合治疗时机的选择提供实验依据.方法 通过对雄性SD大鼠上颌第一磨牙粘固厚度为0.4 mm全冠的方法施加(牙合)干扰,建立大鼠(牙合)干扰模型,分别在建模后2、3、4、5、6d去除(牙合)干扰,并设阳性对照组(不去除(牙合)干扰)及阴性对照组(假干扰),共7组,每组5只大鼠.建模后1、3、5、7、10、14、21、28 d观察各组大鼠双侧颞肌和咬肌机械痛觉过敏的情况,即测定机械刺激反应阈值.结果 阳性对照组大鼠施加(牙合)干扰后大鼠双侧咀嚼肌机械刺激反应阈值持续降低,7d达到最低点,之后部分回升,各时间点与阴性对照组间差异均有统计学意义(P＜0.05).去除(牙合)干扰后各组大鼠双侧咀嚼肌机械刺激反应阈值逐渐恢复,2、3、4、5d去除干扰组大鼠双侧咀嚼肌机械刺激反应阈值分别在建模后10、14、14、21d与阴性对照组差异无统计学意义(P＞0.05),且左右侧咀嚼肌机械刺激反应阈值差异均无统计学意义(P＞0.05).6d去除干扰组大鼠双侧咀嚼肌机械刺激反应阈值有一定回升,但28 d时[右侧颞肌和咬肌分别为(1.365±0.018)和(1.437±0.024)N]仍显著低于阴性对照组[右侧颞肌和咬肌分别为(1.554±0.040)和(1.546±0.019) N](P＜0.001).结论 (牙合)干扰后5d内去除干扰,大鼠咀嚼肌机械痛觉过敏可恢复正常,且去除干扰的时间越早,恢复得越快.

abstractsObjective To investigate the relationship between the existence of occlusal interference and masticatory muscle hyperalgesia by exploring the stimulus-response relationship between the duration of occlusal interference and masticatory muscle mechanical withdrawal threshold.Methods Occlusal interference with 0.4 mm-thick crowns on rat molars was removed under anaesthesia at 2,3,4,5,and 6 d after wear,and masticatory muscle mechanical withdrawal threshold was tested at 1,3,5,7,10,14,21 and 28 d.Results Decreased mechanical withdrawal thresholds were detected in temporal muscles and masseter muscles on both sides following occlusal interference(P＜0.05).After removal of crowns at 2,3,4 and 5 d,rats exhibited the similar head withdrawal thresholds as the sham-application control in masticatory muscles on both sides at 10,14,14 and 21 d(P＞0.05).No significant differences were detected between the contralateral side with the ipsilateral side(P＜0.05).After removal of crowns at 6 d,rats still exhibited significantly decreased head withdrawal thresholds[right temporal muscle:(1.365±0.018) N; right masseter:(1.437 ± 0.024) N] in masticatory muscles on both sides until the last day of the experiment[the sham-application control:right temporal muscle:(1.554± 0.040) N,P＜0.001; right masseter:(1.546± 0.019)N,P＜0.001].Conclusions The mechanical hyperalgesia can disappear after removal of the occlusal interference at 5 d,and the existence of the occlusal interference is positively correlated with the duration of the mechanical hyperalgesia.